America's Army: Proving Grounds

This is the last iteration in the America's Army series that you can still download and play, though you won't find any official servers. I can still hop on and find a few people playing. You're also able to go to the shooting range and through basic training and a few other things. 

Steam Description:

America’s Army: Proving Grounds is the official game of the U.S. Army and part of the highly acclaimed America’s Army game series. This free military game focuses on small unit tactical maneuvers and puts you to the test in a wide variety of new America’s Army maps and AA fan favorites.